Witness to testify she had a threesome with R. Kelly & victim

A woman is set to testify at R. Kelly’s upcoming child pornography trial that she had a three-way sexual encounter with Kelly and the allegedly underage girl shown in the video at the heart of the case.

The 41-year-old R&B superstar is accused of videotaping himself having sex with a girl estimated to be 13 or 14. He has pleaded not guilty. Jury selection is set to begin Friday.

As part of the case, prosecutors claim to have identified the girl in the videotape. This alleged victim is now in her 20s. Kelly’s lawyers plan to argue — and the alleged victim will reportedly testify — that she is not the girl in the tape.

But the prosecution’s new witness could undermine that defense, since she will identify the girl, sources with knowledge of the matter told the Chicago Sun-Times. In addition, the witness is expected to say the girl was underage at the time of their encounter.

“She was involved in a threesome with [the girl] and R. Kelly,” one source said.

Prosecutors and defense lawyers declined to comment, citing a gag order in the case.

The witness’ testimony was among the evidence discussed in secret hearings last month before Judge Vincent Gaughan. The judge, citing concerns about pretrial publicity, closed the hearings to the public and put multiple court filings under seal.

The Sun-Times, Chicago Tribune and the Associated Press filed a legal challenge to unseal the proceedings and documents, as did WBEZ-FM (91.5). Those challenges are still pending.

At one of the closed hearings, Gaughan ruled in the prosecution’s favor and said testimony about the threesome would be admissible at trial, sources said.

In the past, Kelly has faced civil lawsuits from underage girls accusing the singer of inducing them to have sex with him and a second woman. The title track of his 2007 album “Double Up” refers to a man arranging a ménage a trois.

The Kelly case has been pending since June 2002, when the R&B star was indicted on multiple counts of child pornography. It has been delayed repeatedly, but lawyers and courthouse personnel expect it will finally begin May 9.

The indictment followed a more than three-year Chicago Police investigation. The Sun-Times reported on the investigation in a December 2000 story about Kelly’s pattern of pursuing underage girls for sex.

The big break in the case came in February 2002, when a videotape was sent anonymously to the Sun-Times. It shows a man alleged to be Kelly engaging in various sex acts — including urinating on the underage girl. The tape was turned over to the Chicago Police.

Cook County State’s Attorney Richard Devine impaneled a grand jury that heard dozens of witnesses identify Kelly and the teen on the tape and confirm that they had a sexual relationship.

The tape was authenticated by the FBI, which determined it could not have been a forgery.

Kelly, of Olympia Fields, faces up to 15 years in prison if convicted.